[openwrt/openwrt] ipq806x: switch to full dual-boot for the nbg6817 sysupgrade support

[LEDE Commits]

blogic pushed a commit to openwrt/openwrt.git, branch master:
https://git.lede-project.org/4baffa02ce2f3b04be37628f0965b0bade5019cf

commit 4baffa02ce2f3b04be37628f0965b0bade5019cf
Author: Stefan Lippers-Hollmann <s.l-h at gmx.de>
AuthorDate: Thu Jan 18 22:41:44 2018 +0100

    ipq806x: switch to full dual-boot for the nbg6817 sysupgrade support
    
    Instead of writing to the currently booted partition set, this
    implements full dual-boot support for sysupgrade by always writing to
    the other, currently inactive, partition set and toggling the dualflag
    after a successful flash.
    
    The currently active/ booted partition set is determined by parsing
    /proc/cmdline for its rootfs parameter (supplied by the DTS), instead
    of reading from the 0:DUAL_FLAG mtd, in order to prevent (potentially)
    bricking both partition sets.
    
    Signed-off-by: Stefan Lippers-Hollmann <s.l-h at gmx.de>
---
 .../linux/ipq806x/base-files/lib/upgrade/zyxel.sh  | 26 +++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh b/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh
index cf2acfc..ba8e825 100644
--- a/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh
+++ b/target/linux/ipq806x/base-files/lib/upgrade/zyxel.sh
@@ -21,6 +21,7 @@ zyxel_do_flash() {
 	local tar_file=$1
 	local kernel=$2
 	local rootfs=$3
+	local dualflagmtd=$4
 
 	# keep sure its unbound
 	losetup --detach-all || {
@@ -63,6 +64,16 @@ zyxel_do_flash() {
 		umount /tmp/new_root
 	}
 
+	# flashing successful, toggle the dualflag
+	case "$rootfs" in
+		"/dev/mmcblk0p5")
+			printf "\xff" >$dualflagmtd
+			;;
+		"/dev/mmcblk0p8")
+			printf "\x01" >$dualflagmtd
+			;;
+	esac
+
 	# Cleanup
 	losetup -d $loopdev >/dev/null 2>&1
 	sync
@@ -79,12 +90,21 @@ zyxel_do_upgrade() {
 	[ -b "${rootfs}" ] || return 1
 	case "$board" in
 	zyxel,nbg6817)
+		local dualflagmtd="$(find_mtd_part 0:DUAL_FLAG)"
+		[ -b $dualflagmtd ] || return 1
+
 		case "$rootfs" in
 			"/dev/mmcblk0p5")
-				kernel="/dev/mmcblk0p4"
+				# booted from the primary partition set
+				# write to the alternative set
+				kernel="/dev/mmcblk0p7"
+				rootfs="/dev/mmcblk0p8"
 			;;
 			"/dev/mmcblk0p8")
-				kernel="/dev/mmcblk0p7"
+				# booted from the alternative partition set
+				# write to the primary set
+				kernel="/dev/mmcblk0p4"
+				rootfs="/dev/mmcblk0p5"
 			;;
 			*)
 				return 1
@@ -96,7 +116,7 @@ zyxel_do_upgrade() {
 		;;
 	esac
 
-	zyxel_do_flash $tar_file $kernel $rootfs
+	zyxel_do_flash $tar_file $kernel $rootfs $dualflagmtd
 
 	return 0
 }